Blue Moon on Friday 

    Friday, August 31, 2012 is a “blue moon.”  The second full moon within a calendar month is called a blue moon.   There was a full moon on August 1st, so Friday’s full moon is a blue moon.                                  

    The blue moon looks the same as any other full moon.  Why it is called a “blue” moon seems to be lost in antiquity. Blue moons are not as rare as most people realize.  They occur about once every 2 ½ years.  The last blue moon was December 31, 2009, and the next one will be July 31, 2015.

    So be careful when you say that you will do something, such as take the to kids to Disneyland, “once in a blue moon.”  It might come sooner than you think!

                                                                John Charlesworth
    Astronomy Dept.
    Napa Valley College